Droplet actuators are used to conduct a wide variety of droplet operations, such as droplet transport and droplet dispensing. A droplet actuator typically includes a substrate with electrodes arranged for conducting droplet operations on a droplet operations surface of the substrate. Electrodes may include droplet operations electrodes and reference electrodes. Droplets subjected to droplet operations on a droplet actuator may, for example, be reagents and/or droplet fluids for conducting assays. There is a need for improved functionality when conducting droplet operations and for alternative approaches to configuring droplet actuators for conducting droplet operations.
There are various ways of loading reagents and droplet fluids into droplet actuators. Problems with such methods include the risk of introducing air into the fluid and the inability to reliably handle small droplet fluid volumes. Because of these and other problems, there is a need for alternative approaches to loading droplet fluids into a droplet actuator.